1. Field of the Invention
The present invention relates to a heart rate detection method and, more particularly, to a hear rate calculation method for calculating heart rate with heart sound samples at a reduced frequency and identifying the auscultation positions that generate the heart sound for calculating the heart rate having the performance and correlation close to heart rate calculated through electrocardiography.
2. Description of the Related Art
Heart rate is one of the vital signs used to measure the body's basic function and is essential to clinicians' access to patient treatment and evaluation of patient's status. Electrocardiogram (ECG) and phonocardiogram (PCG) can both used to measure heart rate. ECG differs from PCG in that ECG records the electrical activities of the heart while PCG records the sounds the heart produces. Compared to ECG, PCG diagnosis is much easier by placing the stethoscope against one of the auscultation positions.
When experiencing a critical condition, such as pulseless electronic activity (PEA) that is a clinical condition characterized by unresponsiveness and lack of palpable pulse in the presence of cardiac rhythm while can be observed on ECG, the phenomenon of ECG oftentimes leads to misjudgment in diagnosing the critical condition.
In the event of a cardiac emergency caused by cardiovascular diseases, the patient or the wounded person may lose the best chance of saving their lives due to misjudgment, inappropriate first aid measures or long judgment time. How to quickly prepare equipment and position a probe on the patient to collect sufficient data for calculating the heart rate within a short period of time is always one of the top concerns on the list. Currently, a common way of measuring heart rate of a patient or a wounded person is to apply a pulse oximeter to a fingertip of the patient or the wounded person to measure oxygen concentration and transform the oxygen concentration into heart rate, which is very unstable and can be influenced by injured limb or nail decoration, such as nail polish, nail art, and the like.
To cope with the infeasibility or inconvenience upon measuring heart rate at fingertip, an approach of measuring heart rate at other body locations instead of fingertip, which has good performance and acceptable correlation when benchmarking with the measurements of heart rate done by physiological monitors through the means of electrocardiogram (ECG), should be provided.